1. Technical Field
The present invention relates generally to backplanes and more particularly to reconfigurable backplane power distribution.
2. Description of Related Art
A computing shelf generally includes a backplane into which circuit boards are plugged. The backplane is an electronic board containing circuitry and slots for the circuit boards. The backplane may also include slots for input/output (I/O), switching fabrics, synchronization clocks, system management circuitry, and power distribution circuitry. Some backplanes support hot swapping of the plugged-in circuit boards, for example, in large pools of digital signal processors (DSPs) and storage arrays. The backplane layout and circuitry typically dictate the manner in which power is distributed to the circuit boards and the interaction between the circuit boards and the backplane.
In one example, the PCI Industrial Computer Manufacturers Group (PICMG) provides a specification for a telecommunication computing shelf and backplane. This specification, called the PICMG 3.0 Advanced Telecommunications Computing Architecture (ATCA), defines an ATCA computing shelf, an ATCA backplane, and the requirements for the circuit boards when plugged into the ATCA backplane. In particular, the ATCA backplane includes power distribution circuitry that distributes dual independent power feeds from two power entry modules to the circuit boards plugged into circuit board slots on the ATCA backplane. Each circuit board slot receives the power primarily from the first power entry module. Each circuit board slot also receives the power secondarily from the second power entry module. The ATCA backplane is capable of dissipating as much as 200 watts per single-slot circuit board in addition to the power consumption requirements of fans and other ATCA shelf circuitry. In a 16-slot ATCA backplane, over 3200 watts of power must be provided such that each single-slot circuit board may receive the maximum of 200 watts. Circuit boards may occupy more than one circuit board slot to receive more than the maximum 200 watts.
One problem with the ATCA backplane is that the backplane is not designed to support circuit boards requiring more power than the 200 watts per circuit board slot. Circuit boards needing more power may occupy more than one circuit board slot. This, however, may reduce the functionality of the entire ATCA shelf because there are fewer slots available for other circuit boards. Another problem with the ATCA backplane, and backplanes in general, is the time and expense required to upgrade the backplane to support newer circuit boards that require greater power dissipation. Once the backplane is mounted within the computing shelf and the computing shelf is installed on-site, the entire backplane must be replaced with a new backplane that supports the power requirements of the newer circuit boards.